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The functionalization of polysilanes is an important subject in materials science because functionalized polysilanes are expected to exhibit potentially innovative properties. This research aims at the addition of a water-shedding property to polysilanes by introducing perfluoroalkyl groups into their skeleton. The photoinduced iodoperfluoroalkylation of various vinylsilanes takes place successfully upon irradiation with a xenon lamp: vinylmonosilanes undergo iodoperfluoroalkylation with perfluoroalkyl iodides (R f I) regioselectively, and the corresponding perfluoroalkylated silanes are obtained in moderate to high yields. Detailed optimization of the photoinduced iodoperfluoroalkylation has been investigated to apply this method to the functionalization of polysilanes. Polysilanes having vinyl groups can be synthesized by the reductive coupling of dichlorovinylsilanes with samarium diiodide (SmI 2 ) and samarium metal (Sm) upon irradiation with visible light. The synthesized vinylpolysilanes and R f I (about 1.0 mM CHCl 3 solution) are coated on a glass plate sequentially, and then the following photoirradiation with light of a wavelength over 300 nm successfully adds an excellent water-shedding property to the glass plate.

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A method for evaluating and predicting the performance of a newly developed plate-type heat exchanger as an evaporator for water-refrigerant systems such as chillers has been developed. The main component of the developed heat exchanger consists of plates packed together in a casing with winding tubes connected to both sides of the plates. Refrigerant flows inside the tubes, and water flows in the space between the plates. A herringbone-like pattern is formed in this space by the cross sections of the winding tubes. The newly developed method estimates evaporation performance of the developed heat exchanger using new empirical correlations. There are correlations for heat transfer and pressure drop in winding-tube banks on the water side, and correlation for the pressure drop on the refrigerant side.